The present invention relates to a medical glass container with little leaching of alkali components or the like from the inner wall surface of the glass and a method for producing the same.
The invention also relates to a burner for use in inner surface treatment of the medical glass container.
Glass containers for use in storage of pharmaceuticals and the like are generally referred to as “Vial”. The vial is converted from, for example, a borosilicate glass tube. The glass contains alkali components. The alkali components, such as alkali borate, are known to adhere or condense to the inner wall of the vial during conversion. When such alkali components are leached into pharmaceuticals contained in the vial in the case where the vial is used as a storage container of pharmaceuticals, i.e., for medical use, there is a possibility that the pharmaceuticals deteriorate.
As a method for suppressing the leaching of alkali components, a sulfate treatment method to react the alkali components present on the inner surface of the vial converted from a glass tube with sulfate or the like to produce sodium sulfate (Na2SO4), and removing the sodium sulfate by washing with water or a chemical vapor deposition method (CVD method) to coat the inner surface of the vial with a silica (SiO2) thin film is known (Japanese Examined Patent Application Publication No. 6-76233).
Medical vials converted from a borosilicate glass tube are requested to meet the leaching standards of alkali components defined in ISO4802-1, ISO4802-2, and the like. In a process of converting a vial from a borosilicate glass tube, the opening of the vial is first formed, and then the bottom is formed. In a process of forming the bottom, the glass tube is heated at a higher temperature, and thus alkali components or the like volatilize from the glass tube and condense to the inner surface of the vial. Thus, a deteriorated region where the alkali components or the like are likely to leach out is formed on the inner surface of the vial. In order to deal with the problem, so-called low temperature working in which the heating temperature of the glass tube in converting the bottom of the vial is adjusted to a lower temperature is carried out.
It is also known that the leaching of the alkali components are reduced by carrying out fire blast of oxygen-gas flame by a point burner to the deteriorated region on the inner surface of a vial converted from the glass tube while rotating the vial (International Publication No. WO2006/123621). The method has advantages in that other compounds are not required to be introduced into the vial and the number of processing for converting a vial with less leaching of alkali components is small.